I've been a member of the AIIM PDF/UA (Universal Accessibility) working group for a couple of years and the group is close to submitting a proposal as to what is required for a PDF document to be accessible. Not too surprisingly, my focus has been on making the math accessible. At Design Science, we've done a lot of background work and came up with a plug-in to Acrobat and Adobe Reader that does pretty much what the MathPlayer plug-in for IE does: convert math to speech (and soon braille), sync highlight, and magnify the math. The key to making this work is getting MathML into PDF.
Adobe has controlled what is in PDF since they created it. However, a year ago or so, Adobe turned PDF over to ISO to become an official standard called ISO 32000. ISO has a very formal, deliberative (and slow) process for something to become a standard. As a first step towards math accessibility, the PDF/UA committee forwarded Design Science's math proposal to the US ISO Committee. The US Committee accepted the proposal and will present it and support it at an international ISO meeting in Beijing this week.
This is one small step on a long journey toward standardization. With the meeting taking place in Beijing, it seems appropriate to quote a famous Chinese philosopher, "A journey of a thousand miles begins with a single step." I'm happy to say the journey has begun.
To find out more about this and other accessibility work that Design Science is involved in, take a look at this accessibility solutions and the other accessibility solutions pages at the Design Science website.